Self-broaching, rotatable, push-in interbody spinal fusion implant and method for deployment thereof

Abstract

An interbody spinal fusion implant for insertion across a disc space between adjacent vertebral bodies of a human spine has a body two top side and two bottom side junctions, with at least a pair of diagonally opposed junctions having a distance therebetween that does not significantly exceed the implant body height. The implant also includes one or more bone penetrating protrusions extending outwardly from at least the upper and lower walls of the implant. The implant is inserted on its side between adjacent vertebral bodies and then rotated 90 degrees into place. The protrusions penetrate the endplates upon rotation, thereby securing the implant within the spine. The implant has at least one passage therethrough from the upper wall to the lower wall to promote fusion through the implant. Because of the specialized opposed junctions overdistraction between the adjacent vertebral bodies is avoided when the implant is rotated from an initial insertion position to a final deployed position. In one suggested implant set, two implants are rotated in opposite directions into their respective final deployed positions, and a third specialized implant is positioned therebetween to lock the three implants together along cooperating surfaces. A method for deploying the push-in implants is also disclosed.

What I claim is:  
     
         1 . An interbody spinal fusion implant for insertion across a disc space between adjacent vertebral bodies of a human spine, the implant comprising: 
 a body having an insertion end, a trailing end, an upper wall, a lower wall, and opposed side walls, said body having a cross-section with a height measured between said upper and lower walls and a width measured between said side walls, said side walls intersecting said upper and lower walls at four junctions, a first pair of diagonally opposed junctions having a distance therebetween substantially the same as the height of said body, a second pair of diagonally opposed junctions having a distance therebetween greater than the distance between said first pair of diagonally opposed junctions; and    fins extending outwardly from said opposed upper and lower walls adapted to penetrate and extend within the vertebral endplates of the adjacent vertebral bodies upon rotation of the implant approximately 90 degrees from an initial insertion position to a final deployed position.    
     
     
         2 . The implant of    claim 1   , wherein said side walls have a distance therebetween adapted to contact the adjacent vertebral bodies upon initial insertion of said implant into the spine.  
     
     
         3 . The implant of    claim 1   , wherein each of said side walls are planar.  
     
     
         4 . The implant of    claim 3   , wherein said side walls are generally parallel to one another.  
     
     
         5 . The implant of    claim 1   , wherein the shape of each of said side walls is substantially a parallelogram.  
     
     
         6 . The implant of    claim 1   , wherein said upper and lower walls have a distance therebetween adapted to support the vertebral endplates of the adjacent vertebral bodies upon rotation of said implant from an initial insertion position to a deployed position in the disc space.  
     
     
         7 . The implant of    claim 1   , wherein the adjacent vertebral bodies are spaced apart at least in part further in the final deployed position than in the initial insertion position.  
     
     
         8 . The implant of    claim 1   , wherein said upper and lower walls have at least one opening allowing for communication between said upper and lower walls, said opening being capable of containing fusion promoting materials for promoting bone ingrowth through said implant from the vertebral endplate of one of the adjacent vertebral bodies to the vertebral endplate of the other of said adjacent vertebral bodies for fusion of said adjacent vertebral bodies.  
     
     
         9 . The implant of    claim 1   , wherein said upper and lower walls are disposed at least in part in a diverging angular relationship to each other from said insertion end to said trailing end of said body.  
     
     
         10 . The implant of    claim 1   , wherein said upper and lower walls are disposed at least in part in a converging angular relationship to each other from said insertion end to said trailing end of said body.  
     
     
         11 . The implant of    claim 1   , wherein said upper and lower walls have a generally anatomical shape configured to substantially match the natural contours of that portion of the endplates of the two adjacent vertebral bodies to be fused to which said walls are applied.  
     
     
         12 . The implant of    claim 1   , wherein said first pair of diagonally opposed junctions are arcuate.  
     
     
         13 . The implant of    claim 12   , wherein said arcuate junctions are arcs of radii.  
     
     
         14 . The implant of    claim 13   , wherein said arcs of radii are each of the same radius.  
     
     
         15 . The implant of    claim 13   , wherein said arcs of radii have a radius defining a portion of the same circle.  
     
     
         16 . The implant of    claim 13   , wherein said arcs of radii comprise chords of a circle.  
     
     
         17 . The implant of    claim 16   , wherein said arcs of radii comprise chords of the same circle.  
     
     
         18 . The implant of    claim 16   , wherein said arcs of radii comprise quadrants of the same circle.  
     
     
         19 . The implant of    claim 13   , wherein the distance between said arcs of radii generally approximates the height of said body.  
     
     
         20 . The implant of    claim 13   , wherein the distance between said arcs of radii is slightly less than the height of said body.  
     
     
         21 . The implant of    claim 13   , wherein the distance between said arcs of radii is slightly greater than the height of said body.  
     
     
         22 . The implant of    claim 19   , wherein the height of said body is no greater than the width of said body, and said fins extend from said upper and lower walls a height sufficient to make the overall height of said implant, when in the final deployed position as measured across the fins, greater than the width of said body.  
     
     
         23 . The implant of    claim 19   , wherein the height of said body is greater than the width of said body, and said fins extend from said upper and lower walls.  
     
     
         24 . The implant of    claim 1   , wherein said first pair of diagonally opposed junctions are chamfered.  
     
     
         25 . The implant of    claim 1   , wherein said second pair of diagonally opposed junctions are corners.  
     
     
         26 . The implant of    claim 25   , wherein each of said corners form approximately a 90 degree angle.  
     
     
         27 . The implant of    claim 1   , wherein each of said corners form an angle between 45 and 135 degrees.  
     
     
         28 . The implant of    claim 1   , wherein said second pair of diagonally opposed junctions are chamfered.  
     
     
         29 . The implant of    claim 1   , wherein said second pair of diagonally opposed junctions are radiused.  
     
     
         30 . The implant of    claim 1   , wherein said fins have a height measured from the longitudinal central axis of said implant, said height being substantially uniform along a portion of the length of said implant.  
     
     
         31 . The implant of    claim 1   , wherein said fins have a height measured from the longitudinal central axis of said implant, said height being variable along the length of said implant.  
     
     
         32 . The implant of    claim 1   , wherein said fins have a height measured from each of said upper and lower walls, respectively, said height being varied along the length of said implant.  
     
     
         33 . The implant of    claim 1   , wherein said fins have a height measured from each of said upper and lower walls, respectively, said height being substantially constant along the length of said implant.  
     
     
         34 . The implant of    claim 1   , wherein said fins have a sharp leading edge for penetrating the vertebral endplates upon rotation of said implant.  
     
     
         35 . The implant of    claim 1   , wherein said fins are protrusions.  
     
     
         36 . The implant of    claim 1   , wherein said fins are evenly spaced along at least a portion of said upper and lower walls.  
     
     
         37 . The implant of    claim 1   , wherein said implant is configured to have a single direction of rotation such that in rotating said implant 45 degrees said first pair of diagonally opposed junctions has a diagonal substantially the same as the height of said body of said implant contacting the adjacent vertebral bodies prior to rotation.  
     
     
         38 . The implant of    claim 1   , wherein said implant is configured to have a single direction of rotation such that in rotating said implant 45 degrees said first pair of diagonally opposed junctions has a diagonal slightly less than the width of said body of said implant contacting the adjacent vertebral bodies prior to rotation.  
     
     
         39 . The implant of    claim 1   , wherein said implant is configured to have a single direction of rotation such that in rotating said implant 45 degrees said first pair of diagonally opposed junctions has a diagonal slightly greater than the width of said body of said implant contacting the adjacent vertebral bodies prior to rotation.  
     
     
         40 . The implant of    claim 1   , wherein said body has a hollow portion.  
     
     
         41 . The implant of    claim 40   , wherein said hollow portion is adapted to contain fusion promoting material.  
     
     
         42 . The implant of    claim 40   , wherein said upper and lower walls have at least one opening passing therethrough in communication with said hollow portion.  
     
     
         43 . The implant of    claim 42   , wherein said side walls have at least one opening passing therethrough in communication with said hollow portion.  
     
     
         44 . The implant of    claim 1   , wherein said implant is capable of retaining fusion promoting material.  
     
     
         45 . The implant of    claim 40   , wherein at least one of said leading end and said trailing end of said body has an opening in communication with said hollow portion and adapted to cooperatively engage a cap.  
     
     
         46 . The implant of    claim 45   , further comprising a removable cap for closing said opening in at least one of said leading end and said trailing end of said body.  
     
     
         47 . The implant of    claim 42   , wherein at least some of said openings have a maximum cross sectional dimension of approximately 0.5 mm to 5 mm.  
     
     
         48 . The implant of    claim 42   , wherein at least some of said openings are greater than microscopic size.  
     
     
         49 . The implant of    claim 42   , wherein said at least one opening includes a plurality of openings of which a portion are less than 15 microns across their largest dimension.  
     
     
         50 . The implant of    claim 42   , wherein at least some of said openings pass through said upper and lower walls forming channels through said body.  
     
     
         51 . The implant of    claim 1   , wherein said body has a plurality of openings passing therethrough adapted to allow bone to grow through said implant from one of the adjacent vertebral bodies to another of the adjacent vertebral bodies.  
     
     
         52 . The implant of    claim 1   , wherein said implant is made of a material that is stronger than bone.  
     
     
         53 . The implant of    claim 1   , wherein said implant is made of a material that is harder than bone.  
     
     
         54 . The implant of    claim 1   , wherein said implant is made of a surgical grade implant material that is metallic.  
     
     
         55 . The implant of    claim 1   , wherein at least a portion of said body is porous.  
     
     
         56 . The implant of    claim 1   , wherein at least a portion of said body is treated to promote bone ingrowth between said implant and one of the vertebral bodies.  
     
     
         57 . The implant of    claim 1   , for use in the lumbar spine wherein said body has a length in the range of 20-34 mm.  
     
     
         58 . The implant of    claim 57   , wherein said side walls are spaced from one another in the range of 6-20 mm.  
     
     
         59 . The implant of    claim 57   , wherein said upper and lower walls are spaced from one another in the range of 6-20 mm.  
     
     
         60 . The implant of    claim 57   , wherein said fins have a height extending from said upper and lower walls in the range of 1-5 mm.  
     
     
         61 . The implant of    claim 1   , wherein at least one of said ends includes an engagement portion for engaging an instrument for the insertion of said implant.  
     
     
         62 . The implant of    claim 1   , further in combination with a broach having cutting portions adapted to cut a groove corresponding to the shape of said fins into the adjacent vertebral bodies.  
     
     
         63 . The implant of    claim 1   , wherein said implant comprises a material other than bone.  
     
     
         64 . The implant of    claim 1   , wherein said implant comprises bone.  
     
     
         65 . The implant of    claim 64   , wherein said bone includes cortical bone.  
     
     
         66 . The implant of    claim 64   , wherein said implant comprises bone growth promoting material.  
     
     
         67 . The implant of    claim 66   , wherein said bone growth promoting material is selected from one of bone morphogenetic protein, hydroxyapatite, and genes coding for the production of bone.  
     
     
         68 . The implant of    claim 1   , wherein said implant is treated with a bone growth promoting substance.  
     
     
         69 . The implant of    claim 1   , wherein said implant is at least in part bioabsorbable.  
     
     
         70 . The implant of    claim 1   , wherein said implant comprises metal.  
     
     
         71 . The implant of    claim 70   , wherein said metal is ASTM material suitable for use in said implant.  
     
     
         72 . The implant of    claim 70   , wherein said includes titanium.  
     
     
         73 . The implant of    claim 1   , wherein said implant comprises a plastic material.  
     
     
         74 . The implant of    claim 1   , wherein said implant comprises a ceramic material.  
     
     
         75 . The implant of    claim 1   , wherein said implant is formed of a material that intrinsically participates in the growth of bone from one of the adjacent vertebral bodies to the other of the adjacent vertebral bodies.  
     
     
         76 . The implant of    claim 1   , wherein at least a portion of said implant is treated to promote bone ingrowth between said implant and said adjacent vertebral bodies.  
     
     
         77 . An interbody spinal implant set for insertion across a disc space between adjacent vertebral bodies of a human spine, the implant set comprising: 
 a first implant comprising: 
 a body having an insertion end, a trailing end, opposed side walls, and upper and lower walls, said body having a cross-section with a height measured between said upper and lower walls and a width measured between said side walls, said side walls intersecting said upper and lower walls at four junctions, a first pair of diagonally opposed junctions having a distance therebetween substantially the same as the height of said body, a second pair of diagonally opposed junctions having a distance therebetween greater than the distance of said first pair of diagonally opposed junctions; and  
 fins extending outwardly from said opposed upper and lower walls adapted to penetrate the vertebral endplates of the adjacent vertebral bodies upon rotation of the implant in a first direction substantially 90 degrees from an initial insertion position to a final deployed position; and  
   a second implant comprising: 
 a body having an insertion end, a trailing end, opposed side walls, and upper and lower walls, said body having a cross-section with a height measured between said upper and lower walls and a width measured between said side walls, said side walls intersecting said upper and lower walls at four junctions, a first pair of diagonally opposed junctions having a distance therebetween less than the height of said body, a second pair of diagonally opposed junctions having a distance therebetween greater than the distance of said between said first pair of diagonally opposed junctions; and  
   fins extending outwardly from said opposed upper and lower walls adapted to penetrate the vertebral endplates of the adjacent vertebral bodies upon rotation of the implant in a second direction opposite said first direction and substantially 90 degrees from an initial insertion position to a final deployed position.    
     
     
         78 . The implant set of    claim 77   , further comprising a third implant for placement between said first and second implants, said third implant having contacting surfaces for contacting one of said opposed side walls of each of said first and second implants.  
     
     
         79 . The implant set of    claim 78   , wherein said contacting surfaces of said third implant interconnect with said first and second implants.  
     
     
         80 . The implant set of    claim 78   , wherein said contacting surfaces of said third implant include ridges facing opposite the direction of insertion for inhibiting said third implant from expulsion once inserted between said adjacent vertebral bodies.  
     
     
         81 . The implant set of    claim 80   , wherein said side wall of each of said first and second implants facing toward said third implant includes ridges cooperatively oriented for interlocking with said ridges of said third implant.  
     
     
         82 . The implant set of    claim 77   , wherein said side walls of each of said first and second implants have a distance therebetween adapted to contact the adjacent vertebral bodies upon initial insertion of said implant into the spine.  
     
     
         83 . The implant set of    claim 77   , wherein each of said side walls of said first and second implants are planar.  
     
     
         84 . The implant set of    claim 83   , wherein said side walls of each of said first and second implants are generally parallel to one another.  
     
     
         85 . The implant set of    claim 77   , wherein said upper and lower walls of each of said first and second implants have a distance therebetween adapted to support the vertebral endplates of the adjacent vertebral bodies upon rotation of said implant from an initial insertion position to a deployed position in the disc space.  
     
     
         86 . The implant set of    claim 77   , wherein said upper and lower walls of each of said first and second implants have at least one opening allowing for communication between said upper and lower walls, said opening being capable of containing fusion promoting materials for promoting bone ingrowth through said implant from the vertebral endplate of one of the adjacent vertebral bodies to the vertebral endplate of the other of said adjacent vertebral bodies for fusion of the adjacent vertebral bodies.  
     
     
         87 . The implant set of    claim 77   , wherein said upper and lower walls of each of said first and second implants are disposed at least in part in a diverging angular relationship to each other from said insertion end to said trailing end of said body.  
     
     
         88 . The implant set of    claim 77   , wherein said upper and lower walls of each of said first and second implants are disposed at least in part in a converging angular relationship to each other from said insertion end to said trailing end of said body.  
     
     
         89 . The implant set of    claim 77   , wherein said upper and lower walls of each of said first and second implants have a generally anatomical shape configured to substantially match the natural contours of that portion of the endplates of the two adjacent vertebral bodies to be fused to which said walls are applied.  
     
     
         90 . The implant set of    claim 77   , wherein said first pair of diagonally opposed junctions of each of said first and second implants are arcuate.  
     
     
         91 . The implant set of    claim 90   , wherein the distance between said arcs of radii of each of said first and second implants generally approximates the height of said body.  
     
     
         92 . The implant set of    claim 90   , wherein the distance between said arcs of radii of each of said first and second implants is slightly less than the height of said body.  
     
     
         93 . The implant set of    claim 90   , wherein the distance between said arcs of radii of each of said first and second implants is slightly greater than the height of said body.  
     
     
         94 . The implant set of    claim 77   , wherein the height of said body of said first and second implants is no greater than the width of said body of said first and second implants, respectively, and said fins extend from said upper and lower walls of each of said first and second implants a height sufficient to make the overall height of said first and second implants, when in the final deployed position as measured across the fins, greater than the width of said body.  
     
     
         95 . The implant set of    claim 77   , wherein the height of said body of said first and second implants is greater than the width of said body of said first and second implants, respectively, and said fins extend from said upper and lower walls of each of said first and second implants a height sufficient to make the overall height of said first and second implants, when in the final deployed position as measured across the fins, greater than the width of said body.  
     
     
         96 . The implant set of    claim 77   , wherein said first pair of diagonally opposed junctions of at least one of said first and second implants are chamfered.  
     
     
         97 . The implant set of    claim 77   , wherein said second pair of diagonally opposed junctions of at least one of said first and second implants are corners.  
     
     
         98 . The implant set of    claim 77   , wherein said second pair of diagonally opposed junctions of at least one of said first and second implants are chamfered.  
     
     
         99 . The implant set of    claim 77   , wherein said second pair of diagonally opposed junctions of at least one of said first and second implants are radiused.  
     
     
         100 . The implant set of    claim 77   , wherein said fins of said first and second implants have a sharp leading edge for penetrating the vertebral endplates upon rotation of said implant.  
     
     
         101 . The implant set of    claim 77   , wherein said fins of said first and second implants are protrusions.  
     
     
         102 . The implant set of    claim 77   , wherein each of said first and second implants are configured to have a single direction of rotation such that in rotating each of said implants  45  degrees said first pair of diagonally opposed junctions of each of said first and second implants has a diagonal substantially the same as the width of said body of said first and second implants, respectively, contacting the adjacent vertebral bodies prior to rotation.  
     
     
         103 . The implant set of    claim 77   , wherein each of said first and second implants are configured to have a single direction of rotation such that in rotating each of said implants 45 degrees said first pair of diagonally opposed junctions of each of said first and second implants has a diagonal slightly less than the width of said body of said first and second implants, respectively, contacting the adjacent vertebral bodies prior to rotation.  
     
     
         104 . The implant set of    claim 77   , wherein each of said first and second implants are configured to have a single direction of rotation such that in rotating each of said implants 45 degrees said first pair of diagonally opposed junctions of each of said first and second implants has a diagonal slightly greater than the width of said body of said first and second implant, respectively, contacting the adjacent vertebral bodies prior to rotation.  
     
     
         105 . The implant set of    claim 1   , wherein said body of at least one of said first and second implants has a hollow portion.  
     
     
         106 . The implant set of    claim 105   , wherein said hollow portion of said at least one of said first and second implants is adapted to contain fusion promoting material.  
     
     
         107 . The implant set of    claim 105   , wherein said upper and lower walls of at least one of said first and second implants have at least one opening passing therethrough in communication with said hollow portion.  
     
     
         108 . The implant set of    claim 77   , wherein at least one of said first and second implants is capable of retaining fusion promoting material.  
     
     
         109 . The implant set of    claim 105   , wherein at least one of said leading end and said trailing end of said body of at least one of said first and second implants has an opening in communication with said hollow portion and adapted to cooperatively engage a cap.  
     
     
         110 . The implant set of    claim 109   , further comprising a removable cap for closing said opening in at least one of said leading end and said trailing end of said body of at least one of said first and second implants.  
     
     
         111 . The implant set of    claim 77   , wherein at least one of said first and second implants is made of a surgical grade implant material that is metallic.  
     
     
         112 . The implant set of    claim 77   , wherein at least a portion of said body of at least one of said first and second implants is porous.  
     
     
         113 . The implant set of    claim 77   , wherein at least a portion of said body of at least one of said first and second implants is treated to promote bone ingrowth between said at least one implant and one of said vertebra.  
     
     
         114 . The implant set of    claim 77   , wherein at least one of said ends of said first and second implants includes an engagement portion for engaging an instrument for the insertion of said first and second implant.  
     
     
         115 . The implant set of    claim 77   , further in combination with a tap having cutting portions adapted to cut a groove into the adjacent vertebral bodies corresponding to the shape of said fins of at least one of said first and second implants.  
     
     
         116 . A method for deploying at least one interbody spinal fusion implant across a disc space and into adjacent vertebral bodies of a human spine, comprising the steps of: 
 removing at least a portion of the disc from between the adjacent vertebral bodies;    providing a first implant having an insertion end, a trailing end, opposed side walls, upper and lower walls, and fins extending outwardly from said upper and lower walls, said upper and lower walls having openings which pass therethrough so as to allow bone to grow through said first implant from one of the adjacent vertebral bodies to another of the adjacent vertebral bodies, said first implant having a cross-section with said side walls intersecting said upper and lower walls at four junctions, said four junctions including a first pair of diagonally opposed junctions having a distance therebetween less than the height of said body;    inserting said first implant between the adjacent vertebral bodies with said opposed side walls directed toward the adjacent vertebral bodies; and    rotating said first implant into a deployed position such that said fins penetrate the endplates of the adjacent vertebral bodies to access the interior, cancellous regions of the adjacent vertebral bodies.    
     
     
         117 . The method of    claim 1   , wherein the step of removing includes the step of exposing the endplates of the adjacent vertebral bodies by removing sufficient disc material including both annulus fibrosus and nucleus pulposus from between the adjacent vertebral bodies.  
     
     
         118 . The method of    claim 1   , wherein the providing step includes providing said four junctions of said first implant with a second pair of diagonally opposed junctions having a distance therebetween greater than the distance between said first pair of diagonally opposed junctions.  
     
     
         119 . The method of    claim 1   , wherein the providing step includes providing said first implant configured for a single direction of rotation.  
     
     
         120 . The method of    claim 1   , wherein the providing step includes providing said first implant containing a fusion promoting substance.  
     
     
         121 . The method of    claim 1   , wherein the providing step includes providing said first implant with at least one of said leading end and said trailing end of said body having an opening in communication with a hollow portion and adapted to cooperatively engage a cap.  
     
     
         122 . The implant of    claim 6   , wherein the providing step includes providing said first implant in combination with a removable cap for closing said opening in at least one of said leading end and said trailing end of said body.  
     
     
         123 . The method of    claim 1   , further comprising the step of loading said first implant with osteogenic material.  
     
     
         124 . The method of    claim 8   , wherein the step of loading said first implant includes the step of compressively loading said first implant.  
     
     
         125 . The method of    claim 1   , further comprising the step of loading said first implant with osteogenic material prior to the step of inserting.  
     
     
         126 . The method of    claim 10   , wherein the step of loading said first implant includes the step of compressively loading said first implant.  
     
     
         127 . The method of    claim 1   , wherein the inserting step includes the step of contacting said opposed side walls of said first implant with the adjacent vertebral bodies.  
     
     
         128 . The method of    claim 12   , wherein the inserting step includes the sub-step of inducing angulation of the adjacent vertebral bodies.  
     
     
         129 . The method of    claim 13   , wherein the inducing angulation step includes the step of restoring lordosis to the adjacent vertebral bodies.  
     
     
         130 . The method of    claim 13   , wherein the inducing angulation step includes the step of restoring kyphosis to the adjacent vertebral bodies.  
     
     
         131 . The method of    claim 12   , wherein the inserting step includes the sub-step of locating said implant within the implantation space between the adjacent vertebral bodies to a predetermined depth greater than the length of said implant.  
     
     
         132 . The method of    claim 12   , wherein the inserting step includes the sub-step of linearly advancing said implant between the adjacent vertebral bodies.  
     
     
         133 . The method of    claim 17   , wherein the linearly advancing step includes the sub-step of pushing said implant between the adjacent vertebral bodies.  
     
     
         134 . The method of    claim 17   , wherein the linearly advancing step includes the sub-step of driving said implant between the adjacent vertebral bodies with percussion.  
     
     
         135 . The method of    claim 12   , further comprising the step of distracting the adjacent vertebral bodies sufficiently for insertion of said implant prior to the inserting step.  
     
     
         136 . The method of    claim 12   , further comprising the step of attaching a driver for advancement and rotation of said implant between and into the adjacent vertebral bodies prior to the inserting step.  
     
     
         137 . The method of    claim 21   , further comprising the step of detaching the driver from said implant after the rotating step.  
     
     
         138 . The method of    claim 1   , wherein the rotating step includes the step of rotating said first implant approximately 90 degrees.  
     
     
         139 . The method of    claim 1   , wherein the rotating step includes the substep of initiating rotation such that said first pair of diagonally opposed junctions having a distance therebetween less than the height of said body rotates toward the nearest of the adjacent vertebral bodies respectively.  
     
     
         140 . The method of    claim 1   , wherein the rotating step includes the substep of rotating said first implant from its position after the inserting step to a deployed position without substantial additional distraction of the adjacent vertebral bodies.  
     
     
         141 . The method of    claim 1   , wherein the rotating step includes the substep of positioning said upper and lower walls and said fins between the adjacent vertebral bodies to induce angulation of the adjacent vertebral bodies.  
     
     
         142 . The method of    claim 26   , wherein the positioning sub-step includes the step of restoring lordosis to the adjacent vertebral bodies.  
     
     
         143 . The method of    claim 26   , wherein the positioning sub-step includes the step of restoring kyphosis to the adjacent vertebral bodies.  
     
     
         144 . The method of    claim 1   , further comprising the steps of: 
 providing a second implant having an insertion end, a trailing end, opposed side walls, upper and lower walls, and fins extending outwardly from said upper and lower walls, said upper and lower walls having openings which pass therethrough adapted to allow bone to grow through said second implant from one of the adjacent vertebral bodies to another of the adjacent vertebral bodies, said second implant having a cross-section with said opposed side walls intersecting said upper and lower walls at four junctions, said four junctions including a first pair of diagonally opposed junctions having a distance therebetween less than the height of said body;    inserting said second implant between the adjacent vertebral bodies with said opposed side walls facing the adjacent vertebral bodies, said second implant being on an opposite side of the disc space of the adjacent vertebral bodies from said first implant; and    rotating said second implant into a deployed position such that said fins penetrate the end plates of the adjacent vertebral bodies to access the interior, cancellous regions of the adjacent vertebral bodies.    
     
     
         145 . The method of    claim 29   , wherein said step of rotating said first implant includes the step of rotating in a first direction and said step of rotating said second implant includes the step of rotating in a second direction opposite said first direction.  
     
     
         146 . The method of    claim 30   , further comprising the step of providing a space between said first and second implants.  
     
     
         147 . The method of    claim 31   , further comprising the steps of: 
 providing a third implant having an insertion end, a trailing end, opposed side walls, and upper and lower walls, said upper and lower walls having openings which pass therethrough adapted to allow bone to grow through said third implant from one of the adjacent vertebral bodies to another of the adjacent vertebral bodies; and    inserting said third implant during an anterior approach spinal procedure between said first and second implants and between the adjacent vertebral bodies with said opposed upper and lower walls facing the adjacent vertebral bodies.    
     
     
         148 . The method of    claim 32   , wherein the step of inserting said third implant includes the sub-step of contacting said first and second implants with said side walls of said third implant.  
     
     
         149 . The method of    claim 32   , wherein the step of inserting said third implant includes the sub-step of securing said third implant to said first and second implants.  
     
     
         150 . The method of    claim 34   , wherein said securing sub-step includes the sub-step of providing said first, second, and third implants with cooperating grooves located along said respective side walls of said implants in contact with one another.  
     
     
         151 . The method of    claim 29   , wherein the steps of inserting said first and second implants occurs from a posterior aspect of the spine.  
     
     
         152 . The method of    claim 36   , further comprising the step of retracting the dural sac on the posterior side the adjacent vertebral bodies prior to the inserting steps.  
     
     
         153 . The method of    claim 29   , wherein the steps of inserting said first and second implants occurs from an anterior aspect of the spine.  
     
     
         154 . The method of    claim 38   , further comprising the step of retracting the great blood vessels on the anterior side the adjacent vertebral bodies prior to the inserting steps.  
     
     
         155 . The method of    claim 31   , further comprising the step of inserting a rotary broach between the adjacent vertebral bodies, said broach having opposed sides for sliding against the adjacent vertebral bodies and a cutting portion for broaching into each of the adjacent vertebral bodies transverse to the long axis of said broach.  
     
     
         156 . The method of    claim 39   , further comprising the step of rotating said broach so as to the drive cutting elements along the length of cutting portion of the broach into each of the adjacent vertebral bodies transverse to the long axis of the broach.